Hafnium Isotopes and Precambrian Crust-Mantle Evolution

9316255 Patchett该项目将继续Hf和其他同位素研究地壳和地幔化学演化问题，主要有两个目标：（1）完成不同地壳源熔融的花岗岩类的研究，（2）进行新的努力，以确定地质时期新地壳的亏损地幔源。 已从格陵兰、澳大利亚、非洲、加拿大、美国和沙特阿拉伯选择了地体，作为3.8-0.7 Ga期间已知或潜在的大陆新生地体。 为了充分确定贫化源的演化，可能需要进行其他的研究和合作。 这一数据应构成一个坚实的基础，由PI和其他人的壳幔演化4.0 Ga到现在的建模。

9316255 Patchett This project will continue Hf and other isotopic research into problems of crustal and mantle chemical evolution, with two main thrusts: (1) to complete study of granitoids melted from different crustal sources, and (2) to undertake a new effort to definitively determine the depleted mantle source of new crust over geologic time. Terranes have been selected from Greenland, Australia, Africa, Canada, USA and Saudi Arabia as representing known or potential juvenile additions to the continents over 3.8-0.7 Ga. Other terranes and collaborations may become necessary to fully determine the depleted source evolution. This data should constitute a firm basis for modeling by the PIs and others of crust- mantle evolution 4.0 Ga to present.